Gastroparesis and ileus are adverse medical conditions in which normal gastric motor function and/or intestinal peristalsis are impaired. Patients with these conditions typically experience symptoms of nausea or vomiting, and gastric discomfort such as bloating. This can cause reduced food intake and reduced caloric absorption by the intestinal system, which may adversely affect patient health. These conditions are often seen in patients after abdominal surgery or in patients in the intensive care unit. The delayed return to normal gastrointestinal function can result in many days of extra hospitalization, and cause significant complications for patients due to a lack of caloric absorption.
Pacing type stimulation has been proposed to restart peristalsis in post-surgical patients suffering from ileus. For example, U.S. Pat. No. 3,411,507, entitled “Method of Gastrointestinal Stimulation With Electrical Pulses,” describes a transoral system for gastrointestinal (GI) tract pacing to treat ileus. Chen et al., “Gastric pacing improves emptying and symptoms in patients with gastroparesis,” Gastroenterology, 1998 March; 114(3):456-61, also describe pacing to treat ileus. Devices are also available from a number of manufacturers designed to, for example, electrically pace the stomach or GI tract to treat obesity. Such pacing devices are similar in form and function to cardiac pacemakers, and typically consist of a permanently or long-term implanted stimulator and contact leads. A variety of other surgically implanted stimulators have been made and tested to treat other conditions such as gastrointestinal paresis.
In addition to stimulation, there are many situations in which it may be desirable to monitor conditions within, or stimulate or manipulate tissue of the GI tract. For example, devices such as pill-shape cameras are placed into the GI tract by swallowing and allowed to pass through via natural peristaltic transport and excretion. Other devices allowed to pass through the GI tract include certain anastomosis devices used to join the ends of the GI tract together after resection surgery. After sufficient time, the devices fragment or fall apart after portions of them dissolve, and the resulting fragments pass.
However, many known devices or solutions to gastric stimulation or sensing have various drawbacks related to invasive placement or removal, or for existing temporary devices, awkward delivery and a limited time of treatment.
It is known from the surgical literature that non-resorbable foreign matter which is left in contact with the outer wall (serosa) of the stomach or gastrointestinal tract can become integrated into the wall of the GI tract. Over the course of days to weeks, it can actually migrate partially or completely through the wall of the GI tract. Suture, peri-strips, hernia mesh, and silicone bands have all been reported in the clinical literature as having undergone transmural migration.
Transmural device migration can become a significant complication when it happens unexpectedly, such as has occurred with some gastric surgery devices. These incidents often require surgical or laparoscopic or endoscopic interventions. Partial migrations through the wall almost always require surgical intervention. In some cases, however, the materials or devices migrate completely into the GI tract, and are removed endoscopically. It is unknown how often and whether complete device migrations go undetected and simply pass through the GI tract and out of the body.